Tuesday 25th August 2015
When we put a strawberry into our mouths we experience an explosion of sweetness. We are able to do this because of the taste receptors on our tongue – they allow us to identify the difference between salty, sour, bitter, sweet and umami. However, it is thought that there may be others yet to be found as some of our taste receptors don’t respond to the five basic taste groups.
The prime candidates are fat and metal (like when sucking a cut finger), but there are also other possibilities such as calcium and capsaicin – the heat from chili peppers. Recently there has also been talk of kokumi – Japanese for full-bodied taste. There are evolutionary arguments for being able to detect fat and metal, but studies are not clear if fat is a primary taste or modifies the others in some way and metal is hard to isolate as it interacts in many different ways.
Kokumi is thought to give food a fuller, richer flavour, however, by itself appears to lack a distinct taste of its own – so can it be classed as a basic taste? We are understanding more about how it interacts with our taste receptors and it may even have potential health benefits. We could reduce the fat, salt and sugar content of food, and then add kokumi to maintain the flavour that low-fat foods tend to lack, which makes them unappealing to many. Though this is still a long way off from hitting our supermarket shelves.
Our tongues are not the only place in which we find taste receptors – the nose plays a large role in helping us identify what we put into our mouths. That is why when we have a cold and our nose is blocked everything has the same bland flavour. Various studies have found taste receptors in the small intestine thought to be involved in stimulating insulin production, the lungs and even in the testicles – what they are doing there, no one really knows.
As scientists continue to play with our food and taste receptors, who knows what else they may find and where!